1. Field of the Invention
The present invention relates to a wireless selective-call receiver and particularly, to a wireless selective-call receiver equipped with a continuous shaky movement detector for detecting any regular or irregular to-and-fro movement of the receiver's body, thereby providing a security function in response to the absence of continuous shaky movement of the receiver's body.
2. Description of the Prior Art
Wireless selective-call receivers are known as pagers.
There are many examples of applications for a wireless selective-call receiver which uses a detected to-and-fro movement of the body of the wireless selective-call receiver. For instance, Japanese Patent Application Laid-Open No. 4-268854 discloses a calling device for portable telephones, which device permits "vibration" to be selected to inform a person of a telephone call when the to-and-fro movement of the body of the portable telephone is detected as the so detected shaky movement indicates that the person has the portable telephone with him. The calling device permits "light" to inform the person of a telephone call when the to-and-fro movement of the body of the portable telephone is not detected, as the person is supposed to leave the telephone somewhere. The manner in which the person is informed of a telephone call can be automatically selected so as to be appropriate for the situation.
Japanese Patent Application Laid-Open No. 7-170550 shows a paging receiver which uses a signal representing the to-and-fro movement of the receiver's body both for counting the number of steps taken by the person while walking and for driving associated means for preventing the person from being informed of a telephone call. Thus, the paging receiver can be used as a step counter, and if the paging receiver is shocked with a force stronger than a predetermined strength, or if it is dropped inadvertently, it will be put in anti-information condition.
Japanese Patent Application Laid-Open No. 8-075497 shows a walking-data-producing device which can produce desired data to the walker in real time.
These conventional wireless selective-call receivers are equipped with means for making an automatic selection between different modes of informing the person of a telephone call depending on whether the to-and-fro movement of the device's body is detected or not, means for displaying the number of steps taken by the walker, or means for putting the telephone in anti-information condition when shocked.
If, however, such a conventional wireless selective-call receiver is lost, it is unavoidable that the contents of private information stored in the receiver leak to others. Consequently the following problems may be caused:
First, assuming that the wireless selective-call receiver which works in the silent-call mode is left somewhere, the owner of the receiver can not easily find the receiver in a short time as he cannot hear the calling sound even if the receiver is in receiving operation.
Secondly, assuming that the wireless selective-call receiver is lost outdoors, there is a fear that information such as important messages, a telephone directory, ready-made sentences prepared by the owner of the receiver, guidances, alarm messages, schedule messages and so forth may be leaked to others.
Assuming that a telecommunication serving company employs a specific accounting system in which a subscriber shall pay for the amount of telephone calls received beyond certain hundreds per month, and that the wireless selective-call receiver is lost outdoors, permitting others to use the receiver, there is a fear that the subscriber is obliged to pay for the amount of undesired telephone receptions.